480 



ARTIFICIAL PROPAGATION OF GROUSF 



The figures needed to apply this formula may he easily secured. By weighing the empty 

 Iray and the tray with eggs on it at the time of setting and hy suhtracting the former from 

 the latter, the weight of the eggs at setting time is determined. The weight loss at any subse- 

 quent point in incubation may be found by similarly finding the weight of the eggs at 

 the desired time and subtracting it from the weight at the lime of setting. 



Many factors, among them temperature, ventilation and outside atmospheric changes, in- 

 fluence the regulation of humidity. Obviously, even though a humidity curve such as tlie one 

 illustrated may represent the optimum, a successful hatch of grouse eggs will not occur unless 

 the other factors are also properly balanced. The correct weight loss, hypothetically. would 

 be represented by a straight line. However, owing to the influence of these other factors, 

 such a line rarely exists. In order to visualize the rate of moisture loss, figure 39 may be 

 helpful since this weight curve represents the moisture loss in a setting of grouse eggs of 

 which 87 per cent hatched. 



I/) 

 o 



I 



o 



12 13 14 



DAYS INCUBATED 

 FIGURE 39. PROGRESSIVE MOISTURE LOSS DURING INCIBATION OF GROUSE EGGS 



Since the early removal of infertile eggs or those with dead germs would complicate the com- 

 putation of weight loss, they arc left in the trays until such determinations are complete. 



Selling and Care of Eggs. While it is best to set the eggs within a few hours after they 

 are collected, they may be stored without undue risk in trays, preferably at temperatures 

 between 40° F. and .SO" F.. since incubation commences at about 60° F. To keep the germ spot 

 or blastoderm from sticking to the shell, the eggs should be turned at least once a day. A tray 



